1. Technical Field
One or more aspects of the present invention relate to an inkjet printer having a subtank capable of expansion and contraction.
2. Description of the Related Art
For example, a conventional inkjet printer includes a bellows-like expandable and contractible subtank that is positioned in an ink path extending between a main tank and a recording head. The subtank temporarily stores ink so as to smoothen the ink supply pressure that varies in accordance with the amount of ink remaining in the main tank.
If a foreign substance other than ink, for example, air or dust enters a recording head, ink discharging failure occurs. Accordingly, the present inventor considered and made a prototype of a positive-pressure purging type inkjet printer in which a foreign substance was removed together with ink from a recording head by compressing and contracting a subtank.
In order to reliably remove the foreign substance from the recording head, it is beneficial to generate a relatively high ink pressure. However, if the ink pressure increases, the pressure in the subtank increases, and the subtank bulges out, the ink pressure decreases and sufficient positive-pressure purging is difficult.
This problem can be solved by forming the subtank of a highly rigid material or by forming the subtank in a shape that provides high rigidity. Unfortunately, this solving method is hardly adequate because the subtank itself is difficult to deform and a great force is needed to contract the subtank.